Liquid crystal displays (LCDs) are widely used flat panel display devices. As is well known to those having skill in the art, a liquid crystal display generally includes a pair of spaced apart substrates with liquid crystals therebetween. Arrays of spaced apart data lines and gate lines define an array of pixels. A thin film transistor (TFT) for each pixel is electrically connected to a data line, a gate line and a pixel electrode.
LCDs may be classified by the orientation of the liquid crystals between the spaced apart substrates. In a twisted nematic (TN) LCD, the long axes of liquid crystal molecules are aligned parallel to the surfaces of the substrates, and the liquid crystal molecules are twisted between the two substrates. In contrast, in an in-plane switching (IPS) ICD, the liquid crystal molecules are rearranged to be parallel to the substrate upon application of an electric field therebetween.
LCDs may also be classified based on the manufacturing method that is used to form the channel region of the thin film transistors. In an etch stop-type LCD, an insulation layer is formed on a channel region of an amorphous silicon layer. Thus, the etch stop LCD may have a stable current characteristic, but the number of masks that arc used may be increased. In contrast, in an etch back-type LCD, an amorphous silicon layer and a doped amorphous silicon layer are successively deposited and etched. Thus, the manufacturing process may be simple, but the amorphous silicon layer may need to be thick to obtain a channel region having a predetermined thickness, since part of the amorphous silicon layer may be removed when etching the doped amorphous silicon layer.
A basic structure for an IPS mode LCD is described in U.S. Pat. 4,345,249 to Togashi. As described in Togashi in a matrix type of LCD, in which an individual switching element is provided for each of the display elements, the electrodes of each display element comprise a first comb-shaped electrode pattern to which a display signal voltage is applied through a switching element, and a second comb-shaped electrode which is held at a reference potential. The first and second comb-shaped patterns are mutually intermeshed and formed upon a single substrate of the LCD. Application of a display signal voltage causes an electric field to be produced in a direction substantially parallel to the substrate plane, to thereby act upon the liquid crystal, rather than in a direction normal to the substrate plane, as in the case of a conventional type of LCD panel. The comb-shaped patterns may include a plurality of fingers that may extend parallel to the data lines, or parallel to the gate lines.
Unfortunately, crosstalk may be produced in an IPS LCD, that may degrade the image quality of the LCD. Specifically, when the reference electrode fingers extend parallel to the data lines and are made of gate metal, crosstalk may occur because the reference electrode lines cross the data lines. The crosstalk may produce a variation of the data signals relative to the reference electrodes. Moreover, a gate line and a reference electrode line may become short circuited, since they are adjacent one another. These short circuits may be difficult to repair. Alternatively, when the reference electrode fingers extend parallel to the gate lines and are made of data metal, crosstalk may occur because the gate lines and the reference electrode lines cross each other. Moreover, a data line and a reference electrode line may become short circuited because these lines are adjacent one another. These short circuits may be difficult to repair.